1. Field of the Invention
The principles disclosed relate to improvements to round balers used for harvesting agricultural crops. The invention relates particularly to a method and apparatus for forming the initial shape of the bale chamber to better ensure the start of the bale formation.
2. Background Art
Large, cylindrical balers have been on the market for a number of years. U.S. patent application Ser. No. 10/719,460, filed on Nov. 21, 2003, now U.S. Pat. No. 7,181,900, which is hereby incorporated by reference, discloses many aspects of a large round baler. In particular, the illustrations show the variation in the configuration of the belts as the bale is formed.
The formation of a bale in a large cylindrical baler begins when the initial crop material enters the bale forming chamber from the entry near the baler's front. Immediately, the direction the initial crop material is traveling must reverse so it may begin rotating to initiate a large, cylindrical bale.
The initial shape of the bale forming chamber is defined by the initial configuration of the belts. A tensioner is provided to maintain appropriate tension on the belts throughout the bale forming operation. Depending on the type of crop and its condition, such as length, rigidity, etc., there may be some resistance to reversing the direction of the initial crop material. In this case, the initialization of the bale may not occur, resulting in a clogged baler and a delay in the baling process.
Some balers make use of a device for shaping the bale chamber and a second device for tensioning the belt. It will be understood this adds complexity and cost to the baler, while increasing the number of moving parts and the consequent maintenance and failure rate.
The prior art large round baler 100 is illustrated in FIGS. 1a and 1b. The one-piece tensioner arm 110 is clearly shown tensioning the belts 120 in a bale starting position. As the bale grows, the tensioner arm 110 pivots counterclockwise about a pivotal axis 130 to allow the bale to grow and to continue to provide tension to the belts 120.
As long as the crop 140 is able to break over and begin to curl forward, as shown in FIG. 1a, the bale will initiate and begin to grow. A problem occurs if the crop 140 does not break over, as shown in FIG. 1b. In this latter case, the bale is not likely to initialize, instead, the crop 140 will begin to clog up in the baler 100.
Therefore, there is a need for a large round baler with a tensioner providing both belt tension throughout the bale forming process and the initial bale forming chamber shape to better ensure the initialization of the bale.